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	<head>
		<title>three.js - WebGPU - Compute Particles</title>
		<meta charset="utf-8">
		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
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		<div id="info">
			<a href="https://threejs.org" target="_blank" rel="noopener">three.js</a> WebGPU - Compute - 1M Particles
			<div id="timestamps" style="
				position: absolute;
				top: 60px;
				left: 0;
				padding: 10px;
				background: rgba( 0, 0, 0, 0.5 );
				color: #fff;
				font-family: monospace;
				font-size: 12px;
				line-height: 1.5;
				pointer-events: none;
				text-align: left;
			"></div>
		</div>

		<script type="importmap">
			{
				"imports": {
					"three": "../build/three.webgpu.js",
					"three/tsl": "../build/three.webgpu.js",
					"three/addons/": "./jsm/"
				}
			}
		</script>

		<script type="module">

			import * as THREE from 'three';
			import { Fn, uniform, texture, instanceIndex, float, hash, vec3, storage, If } from 'three/tsl';

			import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
			import Stats from 'three/addons/libs/stats.module.js';

			import { GUI } from 'three/addons/libs/lil-gui.module.min.js';

			const particleCount = 1000000;

			const gravity = uniform( - .0098 );
			const bounce = uniform( .8 );
			const friction = uniform( .99 );
			const size = uniform( .12 );

			const clickPosition = uniform( new THREE.Vector3() );

			let camera, scene, renderer;
			let controls, stats;
			let computeParticles;

			const timestamps = document.getElementById( 'timestamps' );

			init();

			function init() {

				const { innerWidth, innerHeight } = window;

				camera = new THREE.PerspectiveCamera( 50, innerWidth / innerHeight, .1, 1000 );
				camera.position.set( 15, 30, 15 );

				scene = new THREE.Scene();

				// textures

				const textureLoader = new THREE.TextureLoader();
				const map = textureLoader.load( 'textures/sprite1.png' );

				//

				const createBuffer = () => storage( new THREE.StorageInstancedBufferAttribute( particleCount, 3 ), 'vec3', particleCount );

				const positionBuffer = createBuffer();
				const velocityBuffer = createBuffer();
				const colorBuffer = createBuffer();

				// compute

				const computeInit = Fn( () => {

					const position = positionBuffer.element( instanceIndex );
					const color = colorBuffer.element( instanceIndex );

					const randX = hash( instanceIndex );
					const randY = hash( instanceIndex.add( 2 ) );
					const randZ = hash( instanceIndex.add( 3 ) );

					position.x = randX.mul( 100 ).add( - 50 );
					position.y = 0; // randY.mul( 10 );
					position.z = randZ.mul( 100 ).add( - 50 );

					color.assign( vec3( randX, randY, randZ ) );

				} )().compute( particleCount );

				//

				const computeUpdate = Fn( () => {

					const position = positionBuffer.element( instanceIndex );
					const velocity = velocityBuffer.element( instanceIndex );

					velocity.addAssign( vec3( 0.00, gravity, 0.00 ) );
					position.addAssign( velocity );

					velocity.mulAssign( friction );

					// floor

					If( position.y.lessThan( 0 ), () => {

						position.y = 0;
						velocity.y = velocity.y.negate().mul( bounce );

						// floor friction

						velocity.x = velocity.x.mul( .9 );
						velocity.z = velocity.z.mul( .9 );

					} );

				} );

				computeParticles = computeUpdate().compute( particleCount );

				// create nodes

				const textureNode = texture( map );

				// create particles

				const particleMaterial = new THREE.SpriteNodeMaterial();
				particleMaterial.colorNode = textureNode.mul( colorBuffer.element( instanceIndex ) );
				particleMaterial.positionNode = positionBuffer.toAttribute();
				particleMaterial.scaleNode = size;
				particleMaterial.depthWrite = false;
				particleMaterial.depthTest = true;
				particleMaterial.transparent = true;

				const particles = new THREE.Mesh( new THREE.PlaneGeometry( 1, 1 ), particleMaterial );
				particles.count = particleCount;
				particles.frustumCulled = false;
				scene.add( particles );

				//

				const helper = new THREE.GridHelper( 60, 40, 0x303030, 0x303030 );
				scene.add( helper );

				const geometry = new THREE.PlaneGeometry( 1000, 1000 );
				geometry.rotateX( - Math.PI / 2 );

				const plane = new THREE.Mesh( geometry, new THREE.MeshBasicMaterial( { visible: false } ) );
				scene.add( plane );

				const raycaster = new THREE.Raycaster();
				const pointer = new THREE.Vector2();

				//

				renderer = new THREE.WebGPURenderer( { antialias: true, trackTimestamp: true } );
				renderer.setPixelRatio( window.devicePixelRatio );
				renderer.setSize( window.innerWidth, window.innerHeight );
				renderer.setAnimationLoop( animate );
				document.body.appendChild( renderer.domElement );

				stats = new Stats();
				document.body.appendChild( stats.dom );

				//

				renderer.compute( computeInit );

				// click event

				const computeHit = Fn( () => {

					const position = positionBuffer.element( instanceIndex );
					const velocity = velocityBuffer.element( instanceIndex );

					const dist = position.distance( clickPosition );
					const direction = position.sub( clickPosition ).normalize();
					const distArea = float( 6 ).sub( dist ).max( 0 );

					const power = distArea.mul( .01 );
					const relativePower = power.mul( hash( instanceIndex ).mul( .5 ).add( .5 ) );

					velocity.assign( velocity.add( direction.mul( relativePower ) ) );

				} )().compute( particleCount );

				//

				function onMove( event ) {

					pointer.set( ( event.clientX / window.innerWidth ) * 2 - 1, - ( event.clientY / window.innerHeight ) * 2 + 1 );

					raycaster.setFromCamera( pointer, camera );

					const intersects = raycaster.intersectObjects( [ plane ], false );

					if ( intersects.length > 0 ) {

						const { point } = intersects[ 0 ];

						// move to uniform

						clickPosition.value.copy( point );
						clickPosition.value.y = - 1;

						// compute

						renderer.compute( computeHit );

					}

				}

				// events

				renderer.domElement.addEventListener( 'pointermove', onMove );
				//

				controls = new OrbitControls( camera, renderer.domElement );
				controls.minDistance = 5;
				controls.maxDistance = 200;
				controls.target.set( 0, 0, 0 );
				controls.update();

				//

				window.addEventListener( 'resize', onWindowResize );

				// gui

				const gui = new GUI();

				gui.add( gravity, 'value', - .0098, 0, 0.0001 ).name( 'gravity' );
				gui.add( bounce, 'value', .1, 1, 0.01 ).name( 'bounce' );
				gui.add( friction, 'value', .96, .99, 0.01 ).name( 'friction' );
				gui.add( size, 'value', .12, .5, 0.01 ).name( 'size' );

			}

			function onWindowResize() {

				const { innerWidth, innerHeight } = window;

				camera.aspect = innerWidth / innerHeight;
				camera.updateProjectionMatrix();

				renderer.setSize( innerWidth, innerHeight );

			}

			async function animate() {

				stats.update();

				await renderer.computeAsync( computeParticles );

				await renderer.renderAsync( scene, camera );

				// throttle the logging

				if ( renderer.hasFeature( 'timestamp-query' ) ) {

					if ( renderer.info.render.calls % 5 === 0 ) {

						timestamps.innerHTML = `

							Compute ${renderer.info.compute.frameCalls} pass in ${renderer.info.compute.timestamp.toFixed( 6 )}ms<br>
							Draw ${renderer.info.render.drawCalls} pass in ${renderer.info.render.timestamp.toFixed( 6 )}ms`;

					}

				} else {

					timestamps.innerHTML = 'Timestamp queries not supported';

				}


			}

		</script>
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